System.Diagnostics.Debug.WriteLine("update selection start:{0} end:{1}", sel.StartCaretPosition, sel.EndCaretPosition);
TextStoreHelper.SetSelectionIndex(this.Controller, this.View, sel.StartCaretPosition, sel.EndCaretPosition);
args.Result = CoreTextSelectionUpdatingResult.Succeeded;
System.Diagnostics.Debug.WriteLine("update selection start:{0} end:{1}", sel.StartCaretPosition, sel.EndCaretPosition);
TextStoreHelper.SetSelectionIndex(this.Controller, this.View, sel.StartCaretPosition, sel.EndCaretPosition);
args.Result = CoreTextSelectionUpdatingResult.Succeeded;